High voltage rectifiers are critical components in high power medical X-ray equipment, such as computed tomography or cardio-vascular systems.
There is a strong demand for high power density and high efficiency, which allows smaller and eventually cheaper systems.
There are some limitation factors in achieving this goal. A major problem exists in keeping the field strength under control which puts a natural limit to miniaturization. Another limitation is parasitic capacitances which increase with smaller dimensions and eventually prevent from efficient use of high operating frequency, required for miniaturization of other components in the power chain.
U.S. Pat. No. 4,569,010 discloses a compact high voltage power supply including a high voltage transformer with individual concentric secondary windings connected to form a ladder network with two series-connected assemblies of diode rectifiers respectively located on corresponding sides of the transformer winding. Preferably, successive secondary windings of larger diameter is each made smaller in width, so as to present substantially the same conductive surface area to each next adjacent winding. In this way the corresponding shunt stray capacitances can be made substantially the same magnitude to equalize the reverse potential distribution across the rectifier diodes.